Hegel's interpretation of (some would say his insight about) contradiction is that... it is more broadly considered as self-defeat. ... Thus the goal of every one of Hegel's post-Phenomenology works are committed to finding some non-self-defeating form of whatever is under consideration. For Marx, communism is the only non-self-defeating economic system. Hence "contradiction" with regard to dialectical materialism ought to be construed as self-defeat and not simply "inconsistent."
Marx's strength was to take [Hegel's dialectics] into the material sphere. So, "contradictions" refers to conflicts over material things - in social terms, of course, access to the means of production. So, the contradictions of capitalism refers to the conflicts over material goods between social groups (i.e. classes, of course.)(Created by and creating all the relations of power and ideology that go with these things.)
If we look at Mao Zedong's On Contradiction, we definitely see the sense of underlying inherent conflict producing novel emergent behavior:
The law of contradiction in things, that is, the law of the unity of opposites, is the basic law of materialist dialectics. Lenin said, "Dialectics in the proper sense is the study of contradiction in the very essence of objects." ... Throughout the history of human knowledge, there have been two conceptions concerning the law of development of the universe, the metaphysical conception and the dialectical conception, which form two opposing world outlooks. Lenin said:Mao goes on to contrast dialectical materialism with "metaphysics" (in the sense of an idealist conception of ontology), mechanical materialism and "vulgar evolutionism":The two basic conceptions of development are: development as decrease and increase, as repetition, and development as a unity of opposites (the division of a unity into mutually exclusive opposites and their reciprocal relation).
The metaphysical or vulgar evolutionist world outlook sees things as isolated, static and one-sided. It regards all things in the universe, their forms and their species, as eternally isolated from one another and immutable. Such change as there is can only be an increase or decrease in quantity or a change of place. Moreover, the cause of such an increase or decrease or change of place is not inside things but outside them, that is, the motive force is external. Metaphysicians hold that all the different kinds of things in the universe and all their characteristics have been the same ever since they first came into being. All subsequent changes have simply been increases or decreases in quantity. They contend that a thing can only keep on repeating itself as the same kind of thing and cannot change into anything different. In their opinion, capitalist exploitation, capitalist competition, the individualist ideology of capitalist society, and so on, can all be found in ancient slave society, or even in primitive society, and will exist for ever unchanged. They ascribe the causes of social development to factors external to society, such as geography and climate. They search in an over-simplified way outside a thing for the causes of its development, and they deny the theory of materialist dialectics which holds that development arises from the contradictions inside a thing. Consequently they can explain neither the qualitative diversity of things, nor the phenomenon of one quality changing into another. In Europe, this mode of thinking existed as mechanical materialism in the 17th and 18th centuries and as vulgar evolutionism at the end of the 19th and the beginning of the 20th centuries.It seems clear that Marx considered bourgeois capitalism to be self-defeating, by its creation and necessary strengthening and disciplining of the proletariat. And he was very nearly right: Socialism and communism were extremely strong in the whole of the industrial world, both Western Europe and the United States. It's always dodgy to speculate on what might have been, but had the socialist leadership been a little more firm, and had the bourgeois leadership a little less ruthless and skillful, the First Global Imperialist War (a.k.a. World War I) might well have resulted in communism becoming the norm. We could just as easily had a superficially popular but spineless political coward like Obama instead of the courageous and risk-taking (even if in service to the bourgeoisie) Roosevelt; Lenin might have been German instead of Russian.
(I hold a syncretic (some might say eclectic or incoherent) view of historical forces: broad, material forces bring conditions to "crisis points", at these points, relatively small characteristics of individual personality have disproportionately large effects. The conditions of Germany before the Second Global Imperialist War would have elevated someone like Hitler to power, but the course of history was shaped in no small part by the particular details of Hitler's individual personality.)
Marx does acknowledge the role of human action in history, but his mention seems an afterthought and doesn't seem to form a critical component of his underlying theory. (Of course, I'm a lousy scholar, so I might easily be mistaken.) In any event, I think that Marx's fundamental view of the self-defeating nature of capitalism and the inevitability of communist revolution seems empirically disproved; Mao's broader view of the self-transformative nature of reality, especially considering the role of human action, intention and teleology in social change, seems more powerful and apt.